Radio spark plug



May29, 1934. H. RABEZZANA um@ SPARK PLUG -F1l6d.F'eb. 25. 1953 Patented May 29, 1934 1,960,317

UNITED STATES PATENT OFFICE ,s

RADIO SPARK PLUG Hector Rabezzana, Flint, Mich., assignor to A C Spark Plug Company, Flint, Mich., a company of Michigan Application February 25, 1933, Serial No. 658,477

Claims. (Cl. 12S-169) .This invention relates to spark plugs and more electrode in the present instance, includes a conparticularly to an improved arrangement and asductor wire or sparking terminal 4, having one sembly of spark plug parts. end projecting beyond the core for cooperation Spark plugs have been constructed heretofore with the side electrode 2 to afford the spark gap,

5 in which the central electrode. is made in sec- With its opposite end carrying a socketed cup 60 tions with one of the sections of a material suitmember 5 seating on the shoulder of the bore. The able for damping or suppressing the electrical cup 5 may be secured to the wire 4 by peening over discharges in the operation of the engine ignithe end of the wire,and the wire is shown vfixed tion system, and which interfere with communiwithin the bore by a thin layer or film of cement 6.

cation through near by radio apparatus. The Seated within the cup 51s one end of the suppres- 65 suppressor section ordinarily used for the purpose Sor section 7, whose opposite end is telescopically of reducing radio interference consists of a stickreceived within the bore of a hollow terminal conlike element of carbon or the like, having the neCtOr section 8, which may project into the bore proper degree of conductance or resistance usually and screw threadedly held in position. The outer of approximately 25,000 ohms resistance, and end of the opening through the terminal 8 may 70 permanently cemented in the bore of the insulabe closed by a suitable plug 9, which may be extor core with its opposite ends in electrical conpanded or threaded into engagement with the tact with the metallic terminal sections of the terminal and which provides a seat for one electrode. Among the diiiiculties encountered in end of a coil spring 10, whose opposite end seats the manufacture of such plugs is the lack of against the suppressor element 'l to maintain it in 75 uniformity in the finished product, due, in a tight engagement with the socket 5. measure, to the fact that the suppressor section, In assembling the core and electrode, preferably which is somewhat porous, absorbs moisture and before the core is secured in the shell 1, the wire 4 cement during the drying out or setting process; and its cap 5 may be introduced into the bore from which changes its character and action, dethe outer end, and after the cap 5 is seated on 30 pending on the degree of permeation. its shoulder the body of cement 6 isk injected One of the objects of the present invention is under pressure from the bottom to completely to promote uniformity of product by the profill the space between the wire 4 and the core 3 vision of an improved assembly of electrode sec- At the same time, cement may be placed on the tions in the insulator core, by which is eliminated interengaging screw threads of the core and g5 the necessity for cementing or otherwise permaterminal 8 and these parts threaded home. Either nently fixing the Suppressor Section in place, before or after the cement has dried, the supf wherebyno change occurs in the composition pressor section 'l may be introduced through the of the suppressor and its subsequent action. bore of the terminal 8 followed by the spring 10,

- Another object is to provide a construction in which is placed under compression by the appli- 90 which the fragile Suppressor SeCtiOn may be easily cation of the closure plug 9. In lieu of the open replaced if it beCOlneS biOken 01' Cracked in use, ended bore through the terminal 8, a socketed so as to avoid the necessity for. discarding the terminajqmay be employed, in which event the entire Speik plug, eS iS the CaSe When the Sup`v suppressor and follow-up spring would be inserted 40 pleSSOI' `iS permanently Cementedlin the 0016- in the bore of the core and terminal, respectively, 95

Additional objects and advantages 0f the C0n prior to the mounting of the connector terminal. struction will be apparent in the course of the As an alternative construction, the sparking following detail description, having reference to terminal and 'connector termina may be conthe accompanying drawing wherein Figure 1 nected as a unit prior to their assembly with the is a vertical Sectional View 0i a Spaikplug 9'5 core, in which event the connection therebetween 100 Sembly enibOdyinS the inVentlOn, and Figure 2 is would involve a suitable insulator. A construca sectional View illustrating e Slight m0 iiflcati0ntion of this sort is illustrated in Figure 2, where 11 Referring t0 the drawing. the numeral 1 indiindicates a cup-shaped member of bakelite or the cates a metallic shell 0r grounding member, heV- like, whose skirt is received within the enlarged ing a screw threaded skirt for engagement with lower portion of the bore of-the connector termi- 105 corresponding threads in the lspark plug opennal 12, and whose apertured base forms 'a seat ing of the engine, and carrying an electrode wire for the head of the pin 13 projecting therethrough.

2. The shell 1 encloses an insulator core 3, of These parts maybe cemented in the core in the porcelain or the like, having a central shouldered usual fashion. Within the cup '11 and bore of the bore to receive the sectional electrode. This terminal 12 is located the suppressor 14 bearing no on the enlarged head of pm 13 'and held in piace Vby the compression spring 15 seating at opposite sections for the now of current therethrough, is

free from any direct connection with the insulator core, so that it may be readily replaced if broken, and that it is not, subjected to any change in its composition in its application and assembly. `Iclaim:

1. In a spark plug, a grounding shell, anine sulator core having a shouldered bore, an electrode carried within the lower portion .of the bore and projected beyond the core to provide a sparking terminal, a socketed head on the electrode, resting on the shoulder of the bore, cementitious material iixing the electrode within the bore, a stick-like element formed of a material suitable for damping electric oscillations and seated within the socketed head for electrical connection with the electrode, a hollow terminal connector at'the outer end of the core, telescopically receiving the stick-like element, a closure plug for the open end of the hollow terminal connector, and a coil spring interposed between said plug and the element to main' ain electrical connection between the parts.

"' 2. A spark plug having a grounding shell and a ,able through the hollow terminal for contact with the sparking terminal, a spring seating at one end on the'elernent' and means closing the outer tact withthe head or said pin, a closure device e end of the hollow terminal and forming a sea for the opposite end of said spring.

3. A spark plug having a grounded shell an an insulator core, a central electrode within the core, including a cup-shaped element of insulating material, a head'pin projecting through the base of the cupped-element, a hollow terminal connector. receiving the4 skirt of the cupped element and forming therewith a pocketan oscillation, damping element within said pocket in confor the outer end of the pocket and a spring bearving at' opposite ends on said closure device and said oscillating damping element. l 4. In a spark plug, an insulator core having a bore therethrough provided with an enlargement at its outer end. a hollow binding post iltted to said enlargement, an electrode section extending through the bore, an insulator member connecting the electrode section and binding post and sealing the hollow interior ot the post and asuppressor element enclosed within the hollow post to electrically bridge the post and electrode section.

5.'In a spark plug, an insulator core having a -100 'ing the wire and core and sealing the'bore, a l105,

hollow binding post rigidly mounted at the outer end of the bore, a suppressor electrode section extending into the hollow binding post at one end and seating within the recess of the head at its other end, and a coil spring within the post'bear- 1- 10'A ing on the suppressorv section to maintain good electrical contact through the parts. j A HECTOR RABEZZANA. 

